diff --git a/dom/tests/mochitest/general/test_interfaces.html b/dom/tests/mochitest/general/test_interfaces.html
index 5d10b3726339..e9de7ae20adc 100644
--- a/dom/tests/mochitest/general/test_interfaces.html
+++ b/dom/tests/mochitest/general/test_interfaces.html
@@ -270,8 +270,6 @@ var interfaceNamesInGlobalScope =
     "CSS",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "CSS2Properties",
-// IMPORTANT: Do not change this list without review from a DOM peer!
-    "CSSCharsetRule",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "CSSConditionRule",
 // IMPORTANT: Do not change this list without review from a DOM peer!
diff --git a/layout/style/test/test_css_eof_handling.html b/layout/style/test/test_css_eof_handling.html
index 3d09b95dcfe5..b54b031dae28 100644
--- a/layout/style/test/test_css_eof_handling.html
+++ b/layout/style/test/test_css_eof_handling.html
@@ -128,16 +128,6 @@ const tests = [
       tst: "td:lang(en"
   },
   
-  {
-      name: "@charset 1",
-      ref: "@charset 'utf-8';",
-      tst: "@charset 'utf-8"
-  },
-  {
-      name: "@charset 2",
-      ref: "@charset 'utf-8';",
-      tst: "@charset 'utf-8'"
-  },
   {
       name: "@media 3",
       ref: "@media all {}",
diff --git a/layout/style/test/test_rule_insertion.html b/layout/style/test/test_rule_insertion.html
index c4aefd96e664..a55ec08c5951 100644
--- a/layout/style/test/test_rule_insertion.html
+++ b/layout/style/test/test_rule_insertion.html
@@ -107,11 +107,6 @@ var innerRuleInfo = [
     return Math.abs(width - (aApplied ? monospaceWidth : serifWidth)) <= 1; // bug 769194 prevents local()
                                              // fonts working on Android
    }],
-  ["@charset 'UTF-8';",
-   function(aApplied, aParent, aException) {
-     // just test whether it threw
-     return aParent instanceof CSSRule ? aException : !aException;
-   }],
   ["@import url(nothing.css);",
    function(aApplied, aParent, aException) {
      // just test whether it threw